MOSCOW, November 9 (RIA Novosti) - Russian President Dmitry Medvedev visited Berlin on Monday for events to mark the fall of the Berlin Wall that led to Germany's unification 20 years ago.

The 160-km barrier, first established in 1961, was the symbol of the Iron Curtain between Western Europe and the Eastern Bloc states until it came down on November 9, 1989, triggering velvet revolutions that toppled communist regimes in the region.

Medvedev is to join other leaders for a formal commemoration of the anniversary. British Prime Minister Gordon Brown, U.S. State Secretary Hillary Clinton, and other top officials are also expected to attend the events.

Chancellor Angela Merkel joined by Mikhail Gorbachev and Lech Walesa, the former Soviet and Polish leaders, made a pilgrimage to the Bornholmer bridge, where the Wall was first breached at the east-west crossing. The bridge is still flanked by remnants of the Wall.

Addressing foreign dignitaries, reporters and members of the public, Merkel said: "Many of you could tell your own story of your way to freedom."

Merkel thanked Gorbachev and Walesa for their role in the Wall's collapse: "You made it possible... Thank you for being here with us today."

The wall fell after Gorbachev had launched the policy of perestroika in the Soviet Union.

Merkel and her guests then went on to a reception hosted by President Horst Koehler.